Jumpers and spoolpieces, known generally as “tie-ins”, are pipeline components used to connect a pipeline, riser or piping structure to another pipeline, riser or piping structure. The term “jumper” is generally used for a vertical arrangement elevated from the seabed or another connection separate from the seabed, whereas “spoolpiece” or “spool” is generally used for an arrangement which is largely horizontal and in contact with the seabed.
Tie-ins such as jumpers and spoolpieces are part of a piping delivery system adapted to deliver fluids often under substantial pressure and at elevated temperature. They are required either to join gaps in a piping system required for geometrical layout reasons, or to act as protection when different structures are adjoined (for example, to prevent overload of manifold or riser structures by mitigating flowline expansion). Tie-ins will frequently be exposed to significant external forces, such as those created by currents. They may be used to join other pipeline components that have a fixed position or which are allowed to move.
A tie-in may be a section of rigid or flexible pipeline (rigid pipe and flexible pipe are both terms of art in offshore pipelaying, as set out in standards such as ISO 13628). A rigid spoolpiece or jumper is typically fabricated from welded steel pipe, whereas a flexible spoolpiece or jumper is typically fabricated from a continuous multi-layer flexible pipe construction.
Effective design of jumpers and spoolpieces is a complex task. When in place, pipelines will move due to temperature and pressure effects. Jumpers and spoolpieces must not only be able to withstand such expansion effects but also be effective to limit the transmission of these effects to other structures that they protect. A large deepwater field may require more than fifty jumpers and spoolpieces.
A conventional design approach will typically involve construction of a complex model of a component design which will then be tested for various output properties in a number of different use cases. The component design will be described in terms of a number of input parameters which are sampled across their range (for example, an input parameter representing a tolerance of between 1 and −1 may be sampled at 1, 0 and −1) to provide a reasonable expectation of exploring extreme stresses and loads on the component. Each of these input parameter value combinations for each use case may require a separate finite element analysis.
The design of these components is thus extremely time-consuming, typically requiring finite element analysis of a large number of cases to provide effective tolerance for misalignment. Spoolpiece and jumper design will frequently form a major part of the engineering design activity required on the pipeline design for such a project.